Chromebook C201 (codename veyron_speedy) support

This introduces Libreboot support for the Asus Chromebook C201 (codename
veyron_speedy). At this point, this produces a standalone Libreboot image that
can be flashed to the RO Coreboot partition of the SPI flash, as well as the
Libreboot version that can be flash to the RO Firmware ID partition.

Libreboot on the Chromebook C201 uses the depthcharge bootloader, modified to
display text messages instead of ChromeOS bitmaps (that encourage the use of
ChromeOS).

For convenience, an installation script, chromebook-flash-replace, is provided
along with a description of the flash layout, to ease the replacement of the
Coreboot and RO Firmware ID partitions on the full SPI flash image.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>

2 files changed, 173 insertions, 0 deletions

diff --git a/resources/libreboot/patch/chromebook/0001-armv7-Word-sized-half-word-sized-memory-operations-f.patch b/resources/libreboot/patch/chromebook/0001-armv7-Word-sized-half-word-sized-memory-operations-f.patch
new file mode 100644
index 00000000..f89b1606
--- /dev/null
+++ b/resources/libreboot/patch/chromebook/0001-armv7-Word-sized-half-word-sized-memory-operations-f.patch
@@ -0,0 +1,89 @@
+From 9746b7bf27d4a3c7c0de78b26ec9f217887f4e7d Mon Sep 17 00:00:00 2001
+From: Paul Kocialkowski <contact@paulk.fr>
+Date: Tue, 22 Sep 2015 22:16:33 +0200
+Subject: [PATCH 1/2] armv7: Word-sized/half-word-sized memory operations for
+ 32/16 bit read/write
+
+Some registers only allow word-sized or half-word-sized operations and will
+cause a data fault when accessed with byte-sized operations.
+However, the compiler may or may not break such an operation into smaller
+(byte-sized) chunks. Thus, we need to reliably perform word-sized operations for
+32 bit read/write and half-word-sized operations for 16 bit read/write.
+
+This is particularly the case on the rk3288 SRAM registers, where the watchdog
+tombstone is stored. Moving to GCC 5.2.0 introduced a change of strategy in the
+compiler, where a 32 bit read would be broken into byte-sized chunks, which
+caused a data fault when accessing the watchdog tombstone register.
+
+The definitions for byte-sized memory operations are also adapted to stay
+consistent with the rest.
+
+Change-Id: I1fb3fc139e0a813acf9d70f14386a9603c9f9ede
+Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
+---
+ src/arch/arm/include/armv7/arch/io.h | 21 +++++++++++++++------
+ 1 file changed, 15 insertions(+), 6 deletions(-)
+
+diff --git a/src/arch/arm/include/armv7/arch/io.h b/src/arch/arm/include/armv7/arch/io.h
+index 9d06003..94cb131 100644
+--- a/src/arch/arm/include/armv7/arch/io.h
++++ b/src/arch/arm/include/armv7/arch/io.h
+@@ -29,40 +29,49 @@
+ 
+ static inline uint8_t read8(const void *addr)
+ {
++	uint8_t val;
++
+ 	dmb();
+-	return *(volatile uint8_t *)addr;
++	asm volatile ("ldrb %0, [%1]" : "=r" (val) : "r" (addr) : "memory");
++	return val;
+ }
+ 
+ static inline uint16_t read16(const void *addr)
+ {
++	uint16_t val;
++
+ 	dmb();
+-	return *(volatile uint16_t *)addr;
++	asm volatile ("ldrh %0, [%1]" : "=r" (val) : "r" (addr) : "memory");
++	return val;
+ }
+ 
+ static inline uint32_t read32(const void *addr)
+ {
++	uint32_t val;
++
+ 	dmb();
+-	return *(volatile uint32_t *)addr;
++	asm volatile ("ldr %0, [%1]" : "=r" (val) : "r" (addr) : "memory");
++	return val;
+ }
+ 
+ static inline void write8(void *addr, uint8_t val)
+ {
+ 	dmb();
+-	*(volatile uint8_t *)addr = val;
++	asm volatile ("strb %0, [%1]" : : "r" (val), "r" (addr) : "memory");
+ 	dmb();
+ }
+ 
+ static inline void write16(void *addr, uint16_t val)
+ {
+ 	dmb();
+-	*(volatile uint16_t *)addr = val;
++	asm volatile ("strh %0, [%1]" : : "r" (val), "r" (addr) : "memory");
+ 	dmb();
+ }
+ 
+ static inline void write32(void *addr, uint32_t val)
+ {
+ 	dmb();
+-	*(volatile uint32_t *)addr = val;
++	asm volatile ("str %0, [%1]" : : "r" (val), "r" (addr) : "memory");
+ 	dmb();
+ }
+ 
+-- 
+1.9.1
+
diff --git a/resources/libreboot/patch/chromebook/0002-chromeos-Allow-disabling-vboot-firmware-verification.patch b/resources/libreboot/patch/chromebook/0002-chromeos-Allow-disabling-vboot-firmware-verification.patch
new file mode 100644
index 00000000..bed24b19
--- /dev/null
+++ b/resources/libreboot/patch/chromebook/0002-chromeos-Allow-disabling-vboot-firmware-verification.patch
@@ -0,0 +1,84 @@
+From d0e6324693214c51e707928e26571ecc9ab8ee03 Mon Sep 17 00:00:00 2001
+From: Paul Kocialkowski <contact@paulk.fr>
+Date: Sun, 9 Aug 2015 10:23:38 +0200
+Subject: [PATCH 2/2] chromeos: Allow disabling vboot firmware verification
+ when ChromeOS is enabled
+
+Some ChromeOS bindings might be wanted without using vboot verification, for
+instance to boot up depthcharge from the version of Coreboot installed in the
+write-protected part of the SPI flash (without jumping to a RW firmware).
+
+Vboot firmware verification is still selected by default when ChromeOS is
+enabled, but this allows more flexibility since vboot firmware verification is
+no longer a hard requirement for ChromeOS (that this particular use case still
+allows booting ChromeOS).
+
+In the future, it would make sense to have all the separate components that
+CONFIG_CHROMEOS enables have their own config options, so that they can be
+enabled separately.
+
+Change-Id: Ia4057a56838aa05dcf3cb250ae1a27fd91402ddb
+Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
+---
+ src/lib/bootmode.c                            | 2 ++
+ src/vendorcode/google/chromeos/Kconfig        | 2 +-
+ src/vendorcode/google/chromeos/vboot2/Kconfig | 4 ++++
+ 3 files changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/src/lib/bootmode.c b/src/lib/bootmode.c
+index f2ff72a..13c0130 100644
+--- a/src/lib/bootmode.c
++++ b/src/lib/bootmode.c
+@@ -80,8 +80,10 @@ void gfx_set_init_done(int done)
+ int display_init_required(void)
+ {
+ 	/* For Chrome OS always honor vboot_skip_display_init(). */
++#if CONFIG_VBOOT_VERIFY_FIRMWARE
+ 	if (IS_ENABLED(CONFIG_CHROMEOS))
+ 		return !vboot_skip_display_init();
++#endif
+ 
+ 	/* By default always initialize display. */
+ 	return 1;
+diff --git a/src/vendorcode/google/chromeos/Kconfig b/src/vendorcode/google/chromeos/Kconfig
+index 8309d19..694e0d7 100644
+--- a/src/vendorcode/google/chromeos/Kconfig
++++ b/src/vendorcode/google/chromeos/Kconfig
+@@ -31,7 +31,6 @@ config CHROMEOS
+ 	select BOOTMODE_STRAPS
+ 	select ELOG
+ 	select COLLECT_TIMESTAMPS
+-	select VBOOT_VERIFY_FIRMWARE
+ 	help
+ 	  Enable ChromeOS specific features like the GPIO sub table in
+ 	  the coreboot table. NOTE: Enabling this option on an unsupported
+@@ -129,6 +128,7 @@ config VIRTUAL_DEV_SWITCH
+ 
+ config VBOOT_VERIFY_FIRMWARE
+ 	bool "Verify firmware with vboot."
++	default y if CHROMEOS
+ 	default n
+ 	depends on HAVE_HARD_RESET
+ 	help
+diff --git a/src/vendorcode/google/chromeos/vboot2/Kconfig b/src/vendorcode/google/chromeos/vboot2/Kconfig
+index 33c33a5..5bd8b54 100644
+--- a/src/vendorcode/google/chromeos/vboot2/Kconfig
++++ b/src/vendorcode/google/chromeos/vboot2/Kconfig
+@@ -16,6 +16,8 @@
+ ## Foundation, Inc.
+ ##
+ 
++if VBOOT_VERIFY_FIRMWARE
++
+ config VBOOT_STARTS_IN_BOOTBLOCK
+ 	bool "Vboot starts verifying in bootblock"
+ 	default n
+@@ -133,3 +135,5 @@ config VBOOT_DYNAMIC_WORK_BUFFER
+ 	  ram to allocate the vboot work buffer. That means vboot verification
+ 	  is after memory init and requires main memory to back the work
+ 	  buffer.
++
++endif # VBOOT_VERIFY_FIRMWARE
+-- 
+1.9.1
+